Permissive weight bearing versus restrictive weight bearing in surgically treated trauma patients with displaced intra-articular calcaneal fractures (the PIONEER study): study protocol for a multicenter randomized controlled trial.

Background: Following successful treatment, displaced intra-articular calcaneal fractures (DIACFs) necessitate an extensive rehabilitation regimen, significantly influencing functional and socio-economic outcomes. Apart from surgical intervention, the implementation of a comprehensive rehabilitation protocol is crucial to optimize foot stability and functional recovery. The objective of this study is to ascertain the optimal rehabilitation protocol for patients with surgically treated DIACFs, either permissive weight bearing (PWB) or Restricted Weight Bearing, focusing on functional outcomes, health-related quality of life (HRQoL), radiographic parameters, cost-effectiveness, and incidence of complications.

Methods: Study design: A prospective multicenter randomized controlled trial.

Study population: Presence of surgically (extended lateral, sinus tarsi, or percutaneous approach) treated unilateral DIACFs (Sanders type II to IV), aged 18-67 years (labor force). Patients must be able to understand and follow weight bearing instructions. N = 115 patients with DIACFs will be included.

Interventions: Patients with DIACFs will be randomly allocated to one of the rehabilitation protocols, either PWB or RWB.

Primary outcome measure: Functional outcome, measured with the American Orthopaedic Foot & Ankle Society Score (AOFAS)).

Secondary outcomes: Functional outcome (Maryland Foot Score, MFS), HRQoL (EuroQol-5D, EQ-5D), differences in radiographic parameters, cost-effectiveness, and complications. Nature and extent of burden: The PWB protocol is aimed to be non-inferior to the RWB protocol. Previous analysis of this protocol in other lower extremity fractures has shown a safe complication rate. Follow-up is standardized according to current trauma guidelines, namely at time points 2, 6, 12 weeks, and 6 months. The radiation exposure for both groups will differ from standard care (one extra CT scan of the foot will be made). Therefore, the burden for participants is considered minimal, with no significant health risks.

Discussion: This study will be the first study to define an optimal rehabilitation regime for surgically treated patients with DIACFs. The limitations of this study include the absence of patient blinding, as this is impossible in rehabilitation. Additionally, the primary outcome measure (AOFAS) has limited validity for DIACFs. However, it is the most commonly used questionnaire in the literature on DIACFs. There is an apparent need since current literature is lacking on this specific topic.

Trial registration: ClinicalTrials.gov NCT05721378, accepted on February 7, 2023.